Apparatus and method for removing a photoresist structure from a substrate

ABSTRACT

In an apparatus and method for removing a photoresist structure from a substrate, a chamber for receiving the substrate includes a showerhead for uniformly distributing a mixture of water vapor and ozone gas onto the substrate. The showerhead includes a first space having walls and configured to receive the water vapor, and a second space connected to the first space so that the water vapor is supplied to and partially condensed into liquid water on one or more walls of the first space. Ozone gas and water vapor without liquid water may be supplied to the second space to form the mixture therein. The showerhead may be heated to vaporize the liquid water on a given surface of the first space.

PRIORITY STATEMENT

This application claims priority to Korean Patent Application No.2005-66374 filed on Jul. 21, 2005 in the Korean Intellectual PropertyOffice, the entire contents of which is hereby incorporated by referenceherein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Example embodiments of the present invention relate in general to anapparatus and a method for removing a photoresist structure from asubstrate.

2. Description of the Related Art

In general, semiconductor devices are manufactured by performing severalprocesses. One process is a fabrication process for forming anelectrical circuit on a silicon wafer that is used as a semiconductorsubstrate. An electrical die sorting (EDS) process is performed forinspecting electrical characteristics of the semiconductor devicesformed by the fabrication process. A packaging process is then performedfor packaging the semiconductor devices in epoxy resins andindividuating the semiconductor devices.

In the fabrication process, a photoresist structure is formed on thesubstrate by a photolithography process. The photoresist structure ispatterned by the photolithography process to form a photoresiststructure on the substrate as a mask pattern for a subsequent process.For example, an etching process is performed on the substrate using thephotoresist structure as an etching mask, so that an electric circuit isformed on the substrate. The photoresist structure is then removed fromthe substrate.

An ozone ashing process using ozone (O₃) gas and a light ashing processusing a light are typically performed to remove the photoresiststructure from the substrate. In the ozone ashing process, a heated gasincluding ozone (O₃) is supplied onto the photoresist structure, and athermal decomposition process is generated in the photoresist structureby the gas including ozone (O₃). This removes the photoresist structurefrom the substrate. In the light ashing process, ultraviolet rayssimultaneously break chemical bonds in the photoresist structure andchange ozone (O₃) gas into activated oxygen (O₂) gas. The activatedoxygen reacts with the photoresist structure having its chemical bondsbroken by the ultraviolet rays, so that oxidation decomposition occursin the photoresist structure to make the photoresist structure stronglyvolatile. Due to this strong volatility, the photoresist structure isremoved from the substrate.

Generally, the chemical reaction between the ozone gas and thephotoresist structure on the substrate tends to occur more actively athigh temperatures. Thus, the higher the temperature in the substrate,the more active the chemical reaction of ozone and the photoresiststructure. However, the higher the temperature of the substrate, thereis also a problem in that there is an increased chance of generatingdefects in the formed semiconductor devices.

For the above reason, the photoresist pattern is removed from thesubstrate at a relatively low temperature. However, the low temperaturein the substrate may markedly reduce the removal rate of the photoresiststructure.

In the above conventional ozone ashing process and in an effort toalleviate problems due to the low temperature, water vapor is added tothe ozone (O₃) gas so as to improve the removal rate of the photoresiststructure in spite of a low temperature of the substrate.

A mixture of ozone (O₃) gas and water vapor is supplied to a first sideof a substrate mounted on a susceptor and is exhausted from a secondside of the substrate opposite to the first side. Because the mixture ofozone (O₃) gas and water vapor is added to the photoresist structure ata high thermal state, the mixture has a higher temperature when added tothe photoresist structure, than when it is exhausted from it.

Accordingly, much more of the photoresist structure adjacent to thefirst side of the substrate is removed than that adjacent to the secondside of the substrate. This is because the photoresist structureadjacent the first side of the substrate is at a higher temperature thanthe photoresist structure adjacent to the second side of the substrate.As a result, the photoresist structure is not removed uniformly from thesubstrate.

To overcome the above-mentioned problem, the mixture of water vapor andozone (O₃) gas is added to a processing chamber and uniformlydistributed onto the substrate including the photoresist structure. Thisis done through a showerhead installed at a top portion of theprocessing chamber. The mixture of water vapor and ozone (O₃) gas isuniformly distributed onto the substrate including the photoresistpattern through the showerhead, and the temperature in the photoresistpattern is substantially maintained at a constant. Hence, thephotoresist pattern is more uniformly removed from the substrate.

However, using a mixture of water vapor and ozone (O₃) gas to bringabout a uniform removal of the photoresist structure may cause otherproblems. Since the substrate including the photoresist structure isheated to a high temperature, the water vapor in the mixture iscondensed and then is instantaneously vaporized. Consequently, themixture makes contact with the heated substrate, which is known in theart as a spot phenomenon. Accordingly, a watermark, which is a trace ofa water drop due to the spot phenomenon, remains on the substrate tocause defects in subsequent processes.

SUMMARY OF THE INVENTION

An example embodiment of the present invention is directed to anapparatus for removing a photoresist structure from a substrate. Theapparatus may include a chamber receiving the substrate, a first gassource for supplying water vapor into the chamber, and a second gassource for supplying ozone gas into the chamber. The apparatus mayinclude a showerhead for uniformly distributing a mixture of the watervapor and ozone gas onto the substrate. The showerhead may include anenclosed first space connected to the first gas source, and a secondspace connected to the second gas source and to the first space so thatthe water vapor is supplied to the first space from the first gas sourceand partially condensed into liquid water on one or more surfaces of thefirst space. The ozone gas and water vapor without liquid water may berespectively supplied to the second space from the second gas source andthe first space to form the mixture therein. The apparatus may include afirst heater heating the showerhead to vaporize the liquid water on agiven surface of the first space.

Another example embodiment of the present invention is directed to amethod of removing a photoresist structure from a substrate. In themethod, water vapor is supplied into an enclosed first space to bepartially condensed into liquid water on surfaces of the first space,and the liquid water is vaporized in the first space. The water vaporwithout any liquid water may be supplied from the first space to asecond space, and ozone gas may be supplied to the second space. Amixture of the water vapor and ozone gas may be uniformly supplied fromthe second space onto the substrate on which the photoresist structureis formed.

Another example embodiment of the present invention is directed to anapparatus for removing a photoresist structure from a substrate. Theapparatus may include a chamber receiving the substrate, and ashowerhead for uniformly distributing a mixture of water vapor and ozonegas onto the substrate. The showerhead includes a first space havingwalls and configured to receive the water vapor, and a second spaceconnected to the first space so that the water vapor is supplied to andpartially condensed into liquid water on one or more walls of the firstspace. The ozone gas and water vapor without liquid water is supplied tothe second space to form the mixture therein. The showerhead is heatedto vaporize the liquid water on a given surface of the first space.

Another example embodiment of the present invention is directed to amethod of removing a photoresist structure from a substrate. In themethod, water vapor is partially condensed into liquid water within afirst space, and the liquid water is vaporized in the first space. Thewater vapor without liquid water is supplied to from the first space toa second space containing ozone gas. A mixture of the water vapor andozone gas is uniformly supplied onto the substrate for removing thephotoresist structure. Any spot phenomenon occurs within the first spaceand not on the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more apparent by describing in detailexample embodiments thereof with reference to the attached drawings,wherein like elements are represented by like reference numerals, whichare given by way of illustration only and thus do not limit the exampleembodiments of the present invention.

FIG. 1 is a structural view illustrating an apparatus for removing aphotoresist structure according to an example embodiment of the presentinvention.

FIG. 2 is a plane view illustrating a bottom surface of a first plate ofa showerhead in FIG. 1.

FIG. 3 is a plane view illustrating a bottom surface of a second plateof a showerhead in FIG. 1.

FIG. 4 is a plane view illustrating a bottom surface of a third plate ofa showerhead in FIG. 1.

FIG. 5 is a flow chart illustrating a method of removing a photoresiststructure according to an example embodiment of the present invention;and

FIG. 6 illustrates a principle of removing photoresist structure usingwater vapor and ozone (O₃) gas.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The present invention is described more fully hereinafter with referenceto the accompanying drawings, in which example embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to the exampleembodiments set forth herein. Rather, these example embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art. Inthe drawings, the size and relative sizes of layers and regions may beexaggerated for clarity.

When an element or layer is referred to as being “on,” “connected to” or“coupled to” another element or layer, it can be directly on, connectedor coupled to the other element or layer or intervening elements orlayers may be present. In contrast, when an element is referred to asbeing “directly on,” “directly connected to” or “directly coupled to”another element or layer, there are no intervening elements or layerspresent. Like numbers refer to like elements throughout. As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms are only used to distinguish oneelement, component, region, layer or section from another region, layeror section. Thus, a first element, component, region, layer or sectiondiscussed below could be termed a second element, component, region,layer or section without departing from the teachings of the exampleembodiments of the present invention.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. These spatially relative termsare intended to encompass different orientations of the device in use oroperation in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas “below” or “beneath” other elements or features would then beoriented “above” the other elements or features. Thus, the term “below”can encompass both an orientation of above and below. The device may beotherwise oriented (rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing exampleembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude plural forms as well, unless the context clearly indicatesotherwise. Terms such as “comprises” and/or “comprising”, when used inthis specification, specify the presence of stated features, integers,steps, operations, elements and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. Terms suchas those defined in commonly used dictionaries should be interpreted ashaving a meaning that is consistent with their meaning in the context ofthe relevant art, and will not be interpreted in an idealized or overlyformal sense unless expressly so defined herein.

FIG. 1 is a structural view illustrating an apparatus for uniformlyremoving a photoresist structure from a substrate according to anexample embodiment of the present invention. Referring to FIG. 1, theapparatus 100 (hereinafter referred to as a “photoresist removalapparatus”) may include a chamber 110, a stage 120, a first heater 130,a showerhead 140, a second heater 150, a first gas source 160 and asecond gas source 170.

The chamber 110 provides a processing space for removing a photoresistfilm or a photoresist pattern (hereafter “photoresist structure”) from asubstrate 200. Chamber 110 may have a cylindrical shape or a cubicshape, for example. An exhaustion hole 112 through which residual gasesare exhausted from chamber 110 is formed at a bottom portion of thechamber 110. An entrance portion (not shown) through which the substrate200 is induced into the chamber 110 is formed at a portion of a sidewallof the processing chamber 110.

Residual gases including a mixture of water vapor and ozone (O₃) gaspass through the exhaustion hole 112 and through a mist trap 180, andare exhausted from the processing chamber 110. The exhaustion hole 112and mist trap 180 are connected to each other through a first exhaustingline 182. The mist trap 180 separates the mixture into water vapor andozone (O₃) gas. Water vapor is condensed into liquid water and theliquid water is exhausted from the photoresist removal apparatus 100through a second exhausting line 184. Ozone (O₃) gas passes through athird exhausting line 186 and is changed into oxygen (O₂) gas in anozone removal unit 190 positioned on a third exhausting line 186 so asto deteriorate toxicity of the ozone (O₃) gas. Accordingly, ozone (O₃)gas is exhausted from the photoresist removal apparatus 100 through thethird exhausting line 186 (including the ozone removal unit 190) asoxygen (O₂) gas.

The stage 120 may be positioned at a lower portion of the chamber 110and supports the substrate 200. The substrate 200 may be horizontallypositioned on the stage 120. The stage 120 may have a disk shape tosupport the substrate 200. In the one example, the stage 120 is composedof a silicon carbide (SiC).

A plurality of guiding pins 122 may be positioned along a peripheralportion of an upper surface of the stage 120. In one example, theguiding pins 122 may generally have a pin shape. The substrate 200 isguided to an accurate position on the stage 120 by the guiding pins 122as the substrate 200 is loaded onto the stage 120.

A plurality of lifting pins 124 may be positioned in penetration holes(not shown) penetrating the stage 120 around the guiding pins 122. Thelifting pins 124 may move vertically along a corresponding penetrationhole. Accordingly, the substrate 200 is loaded onto the stage 120 as thelifting pins 124 move downward. The substrate 200 is unloaded from thestage 120 as the lifting pins 124 move upward.

The first heater 130 is positioned under the stage 120 and heats thesubstrate 200 and photoresist structure. For example, heat istransferred to the stage 120 on which the substrate 200 is positioned bythe first heater 130 and then transferred to the photoresist structureon the substrate 200 from the stage 120 due to thermal conduction. Inone example, the photoresist structure may be heated to a temperature ofabout 98° C. to 100° C. In the present example embodiment, the substrate200 may be heated to a temperature higher than the temperature at whichthe photoresist structure is heated, so as to compensate for heat lossfrom the substrate 200.

While the present example embodiment describes that the first heater 130is positioned under the stage 120, the first heater 130 may bepositioned inside the stage 120 together therewith, as would be evidentto one of ordinary skill in the art.

The showerhead 140 is positioned on an upper portion of the chamber 110and faces the stage 120 in the chamber 110. Ozone (O₃) gas and watervapor used to remove the photoresist structure from the substrate 200are mixed in the showerhead 140 to form a mixture of water vapor andozone (O₃) gas. The mixture is uniformly distributed onto the substrate200 on the stage 120 via showerhead 140. In one example, the showerhead140 may include first, second and third plates 141, 142 and 143, asshown in FIGS. 2 to 4.

FIG. 2 is a plan view illustrating a bottom surface of the first plate141, and FIG. 3 is a plan view illustrating a bottom surface of thesecond plate 142. FIG. 4 is a plan view illustrating a bottom surface ofthe third plate 143. Referring to FIGS. 1 to 4, a top view of theshowerhead 140 illustrates a circle, so that the first, second and thirdplates 141, 142 and 143 may be formed into a circular shape. In FIG. 2,the first plate 141 has a circular shape and a bottom surface of thefirst plate 141 is recessed except for a peripheral portion thereof. Thefirst plate 141 thus includes a recessed portion 148 on the bottomsurface. When the first plate 141 is engaged with the second plate 142,the recessed portion 148 is closed by a top surface of the second plate142 so that a first space 144 is formed between the first and secondplates 141 and 142.

Referring FIG. 3, the second plate 142 has a circular shape with adiameter substantially identical to that of the first plate 141. Abottom surface of the second plate 142 is partially recessed. That is,the second plate 142 has a plurality of grooves 149 at the bottomsurface thereof. The grooves 149 are formed along a circumferentialdirection with a consistent gap distance in a radial direction and incommunication with one another. A plurality of first holes 146 areuniformly arranged on a top surface of the second plate 142 with a givengap distance in the radial direction and in communication with thegrooves 149. As the second plate 142 is engaged with the third plate143, the grooves 149 are closed by a top surface of the third plate 143so that a second space 145 is formed between the second and third plates142 and 143.

Water vapor supplied into the first space 144 may be partially condensedinto liquid water on the surfaces of walls defining the first space 144.This is due to a temperature difference between water vapor and theshowerhead 140. For example, water vapor supplied into the first space144 is condensed on the bottom surface of the first plate 141 and thetop surface of the second plate 142 due to the temperature difference.However, the showerhead 140 may be heated in advance by a second heater150 so that vaporization of the liquid water is generated again, at themoment the liquid water contacts the surfaces of the walls surroundingfirst space 144. That is, the vaporization of the liquid water,described previously as a spot phenomenon, occurs in the showerhead 140.Because undesirable watermarks due to the spot phenomenon remain in theshowerhead 140, the watermarks have no effect on the removal process forthe photoresist structure from the substrate 200.

Referring to FIG. 4, the third plate 143 may have a circular shape witha diameter substantially identical to that of the first plate 141, andincludes a plurality of second holes 147 through which the third plate143 penetrates. The second holes 147 may be uniformly arranged on thethird plate 143 with a given gap distance in a radial direction. Whenthe second and third plates 142 and 143 are engaged, the second holes147 communicate with the second space 145 and are arranged so that thefirst and second holes 146 and 147 alternate with each other, as shownin FIG. 3. Accordingly, the first and second holes 146 and 147 are notdirectly connected with each other. Hence, water vapor supplied throughthe first hole 146 may be prevented from being immediately exhaustedthrough the second hole 147.

Ozone (O₃) gas is supplied into the second space 145, and water vapor inthe first space 144 is provided to the second space 145 through thefirst holes 146. Therefore, water vapor is mixed with ozone (O₃) gas inthe second space 145. The mixture of water vapor and ozone (O₃) gas isuniformly supplied onto the substrate 200 via the second holes 147.

The mixture is heated at a consistent temperature by the second heater150 in the showerhead 140 and uniformly supplied from the showerhead 140over the substrate 200. As the mixture contacts the substrate 200, auniform temperature distribution of temperature of the mixture ismaintained. The photoresist structure may thus be uniformly removed fromthe substrate 200, thereby improving removal uniformity of thephotoresist structure.

The second heater 150 surrounds a side surface and a top surface of theshowerhead 140. The second heater 150 heats the ozone (O₃) gas and watervapor mixture supplied to the shower head 140 to a given temperature.For example, the second heater 150 heats the showerhead 140, and theheated showerhead 140 heats the ozone (O₃) gas and water vapor mixture.The mixture is heated to a temperature in a range of about 98° C. to105° C. In one example, the mixture may be heated to a temperature ofabout 103.5° C. In consideration of thermal budget, the mixture may beheated to a temperature higher than the range of about 98° C. to 105° C.As a result, the showerhead 140 is heated by the second heater 150 sothat as soon as the water vapor is condensed into liquid water onsurfaces of the showerhead 140 in the first space 144, the liquid wateris again vaporized into water vapor.

The first gas source 160 supplies water vapor into the chamber 110. Inone example, the first gas source 160 may include a vaporizer forgenerating water vapor. The first gas source 160 may include a firstreservoir 161 for storing de-ionized water, a vaporizer 162 forvaporizing the de-ionized water to generate the water vapor, and asecond reservoir 163 for storing a carrier gas which transfers the watervapor. The carrier gas may be an inactive gas such as nitrogen gas (N₂),helium gas (He), argon gas (Ar), etc.

The first reservoir 161 is connected to the vaporizer 162 through afirst connecting line 164. A first valve 165 is installed in the firstconnecting line 164 to control flow of the de-ionized water. The secondreservoir 163 is connected to the vaporizer 162 through a secondconnecting line 166, and a second valve 167 is installed to the secondconnecting line 166 to control flow of the carrier gas.

The first gas source 160 is connected to the chamber 110 through a firstsupplying line 168. The first supplying line 168 extends to an inside ofthe chamber 110 and communicates with the first space 144 of theshowerhead 140. A third valve 169 is positioned on the first supplyingline 168 to control a supplying flow of water vapor. While in thepresent example embodiment the first, second and third valves 165, 167and 169 are used to control a supplying flow of a fluid, a mass flowcontroller may be used as an alternative to control a supplying flow ofa fluid, as would be known to one of the ordinary skill in the art.

The de-ionized water is vaporized in the vaporizer 162 and transformedinto water vapor. The water vapor is supplied to the first space 144 ofthe showerhead 140 through the first supplying line 168 by the carriergas. While the present example embodiment shows the first gas source 160as including the vaporizer 162 to vaporize the de-ionized water, thefirst gas source 160 may alternatively include a bubbler to vaporize thede-ionized water, as would be known to one of ordinary skill in the art.

The second gas source 170 supplies ozone (O₃) gas into the chamber 110.In one example embodiment of the present invention, the second gassource 170 includes an ozone generator for generating the ozone (O₃)gas. In an example, oxygen and nitrogen gas are supplied to the ozonegenerator. The oxygen gas and nitrogen gas are mixed together in theozone generator, and a high frequency electric power is applied to themixture to thereby generate the ozone (O₃) gas. In one example, ozone(O₃) gas may be generated only when needed. When ozone (O₃) gas is notrequired, supply of the oxygen gas and nitrogen gas to the ozonegenerator may be discontinued.

The second gas source 170 is connected to the chamber 110 through asecond supplying line 172. The second supplying line 172 extends to aninside of the chamber 110 and connects with the second space 145 of theshowerhead 140. A fourth valve 174 is positioned on the second supplyingline 172 to control a supplying flow of ozone (O₃) gas. While thepresent example embodiment discloses that the fourth valve 174 is usedto control a supply flow of ozone (O₃) gas, a mass flow controller maybe used to control a supply flow of ozone (O₃) gas, as would be known toone of ordinary skill in the art.

When an amount ratio of water vapor with respect to ozone (O₃) gas isnot fixed, the amount ratio may be excessively small or large. When anamount ratio of water vapor with respect to ozone (O₃) gas isexcessively small, a removal rate of the photoresist structure tends tobe negligible, which would reduce productivity. In contrast, when theamount ratio is excessively large, water vapor is substantiallycondensed in the first space 144. Accordingly, in an example embodimentwater vapor and ozone (O₃) gas may be supplied in a fixed ratio.

Water vapor and ozone (O₃) gas is respectively supplied to the chamber110 and mixed with each other in the showerhead 140 positioned inside ofthe chamber 110 for supply to the substrate 200. Since the mixture isuniformly supplied to the substrate 200, the photoresist structure isuniformly removed from the substrate 200.

Water vapor is supplied into the first space 144 at a temperaturedifferent from that of the showerhead 140, so that the spot phenomenonoccurs within the showerhead 140. Accordingly, the spot phenomenon maybe substantially prevented from occurring on a surface of the substrate.

FIG. 5 is a flow chart illustrating a method of removing a photoresiststructure according to an example embodiment of the present invention.Referring to FIG. 5, the substrate 200 on which a photoresist structureis formed is supplied to the chamber 110 using a transferring arm (notshown) and is supported on a lifting pin 124. Then, the lifting pin 124is dropped down so that the substrate 200 is loaded onto a top surfaceof the stage 120. While loaded onto the stage 120, the guiding pin 122guides the substrate 200.

The first heater 130 heats (S110) the substrate 200 loaded on the stage120 to a temperature in a range of about 98° C. to 100° C. Thereafter,de-ionized water is supplied from the first reservoir 161 to thevaporizer 162 through the first connecting line 164 by opening the firstvalve 165. The de-ionized water vaporizes in the vaporizer 162. Inactivegas is supplied from the second reservoir 163 to the vaporizer 162through the second connecting line 166 by opening the second valve 167.Inactive gas transfers water vapor. Water vapor generated at the firstgas source 160 is supplied (S120) to the first space 144 blocked by thefirst plate 141 and the second plate 142 of the showerhead 140 throughthe first supplying line 168.

The temperature of the water vapor and the temperature inside theshowerhead 140 are not always the same. The vapor is condensed on innersurfaces of the first space 144 due to the difference in temperature.

The showerhead 140 is heated to a temperature in a range of about 98° C.to about 105° C. by the second heater 150. In an example, the showerhead140 is heated up to about 103.5° C. by the second heater 150. Thecondensed water is then vaporized (S130) by the heated showerhead 140.

A spot phenomenon where water vapor is condensed and vaporized occurs inthe first space 144 of the showerhead 140. Then, water vapor is heatedby the second heater 150 and supplied to the substrate 200. Therefore,the spot phenomenon does not occur on a surface of the substrate 200.Accordingly, a watermark, which results from the spot phenomenon andrepresents a defect, is not formed on the surface of the substrate 200.

Water vapor is continuously supplied from the first gas source 160 tothe first space 144. The water vapor of the first space 144 is supplied(S140) to the second space 145 blocked by the second plate 142 and thethird plate 143 through the plurality of first holes 146 of the secondplate 142. Ozone (O₃) gas is generated in the ozone generator of thesecond gas source 170. Ozone (O₃) gas is supplied (S150) to the secondspace 145 through the second supplying line 172.

The water vapor and ozone (O₃) gas are uniformly mixed at the secondspace 145 to form a mixture. The mixture is uniformly supplied (S160) tothe substrate 200 supported by the stage 120 through the plurality ofsecond holes 147 of the third plate 143. As the mixture is heated by thesecond heater 150 in the shower head 140, the mixture is uniformlysupplied from the showerhead 140 onto the substrate 200. Hence, thetemperature of the mixture stays constant on all parts of substrate 200.Because the temperature of the mixture is uniform, the photoresiststructure may be uniformly removed from the substrate 200, therebyimproving removal uniformity of the photoresist structure.

The mixture gas for removing the photoresist structure is exhausted fromthe chamber 110 through the exhaustion hole 112. The ozone (O₃) gas andwater vapor are separated from the mixture in a mist trap 180. Watervapor is changed into liquid water and the liquid water is exhaustedthrough a drain. Because ozone (O₃) gas is toxic, it is dissolved intooxygen gas and exhausted from the chamber 100.

In the example method, the water vapor and ozone (O₃) gas are mixed witheach other inside the showerhead 140 and uniformly supplied onto thesubstrate 200. Accordingly, the photoresist structure on the substrate200 is uniformly removed so as to substantially improve removaluniformity.

Moreover in the example method, the spot phenomenon due to vaporizationof water vapor in the chamber 110 occurs not on the surface of thesubstrate 200, but in the first space 144 of the showerhead 140.Accordingly, any watermark due to the spot phenomenon is prevented frombeing formed on a surface of the substrate 200, thereby reducingprocessing defects.

FIG. 6 illustrates a principle of removing a photoresist structure usinga water vapor and ozone (O₃) gas. Referring to FIG. 6, a plurality ofhydroxyl ions (OH—) in a mixture of water vapor (H₂ 0) and ozone (O₃)gas separates hydrophobic groups of a monomer in the photoresist layer210 on the substrate 200. For example, the hydroxyl ions (OH—) producedby a chemical reaction between water vapor and ozone (O₃) gas arereacted with carbons (C) in the monomer. As a result, the hydrophobicgroup (OR) is separated from the monomer.

Because of a combination of the hydroxyl ions (OH—) and a separation ofthe hydrophobic group, the monomer includes oxygen that has a negativeelectrical charge. That is, the monomer includes carboxyl ion (COO—)that has a negative electrical charge. The negatively charged oxygenoffers a site of combination capable of combining a hydrogen ion or analkali ion that has a positive electrical charge.

The hydrophobic group separated from the monomer due to the combinationof the hydroxyl ion (OH—) includes an oxygen ion that has a negativeelectrical charge. The negatively charged oxygen ion is combined withthe hydrogen ion remaining in the photoresist layer 210. Accordingly, ahydroxyl group is generated in the hydrophobic group so that thehydrophobic group may be changed into a hydrophilic group.

The separation of the hydrophobic group from the monomer is performed ata temperature between about 90° C. to 120° C. In one example, this maybe performed at a temperature between about 98° C. to 100° C.

When the combination of the hydroxyl ion (OH—) and the separation of thehydrophobic group from the monomer are performed at a temperature belowabout 90° C., the separation rate of the hydrophobic group from themonomer of the photoresist layer 210 tends to be negligible. Atemperature over about 120° C., a thermal stress is excessively appliedto various patterns on the substrate 200. Thereafter, a cleaningsolution is supplied onto the photoresist layer 210 including a monomerfrom which a hydrophobic group is separated, so that the photoresistlayer 210 is changed to a water-soluble layer. In the present exampleembodiment, the cleaning solution is supplied onto the photoresist layer210 at a temperature between about 90° C. to 120° C.

According to the example embodiments of the present invention, watervapor and ozone (O₃) gas are respectively supplied to the showerhead 140positioned on an upper portion of the chamber 110, and mixed with eachother in the showerhead 140. As a result, the mixture is uniformlysupplied onto the substrate 200. Accordingly, the mixture has a constanttemperature along an entire surface of the substrate 200 so that thephotoresist layer 210 can be uniformly removed from the substrate.Moreover, a spot phenomenon due to the water vapor occurs not on asurface of the substrate 200, but in the showerhead 140. Accordingly,any watermark due to the spot phenomenon is prevented from being formedon the surface of the substrate 200.

The example embodiments of the present invention being thus described,it will be obvious that the same may be varied in many ways. Suchvariations are not to be regarded as departure from the spirit and scopeof the exemplary embodiments of the present invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. In the claims, means-plus-function clauses are intended tocover the structures described herein as performing the recited functionand not only structural equivalents but also equivalent structures.Therefore, it is to be understood that the foregoing is illustrative ofthe present invention and is not to be construed as limited to thespecific embodiments disclosed, and that modifications to the disclosedembodiments, as well as other embodiments, are intended to be includedwithin the scope of the appended claims. The invention is defined by thefollowing claims, with equivalents of the claims to be included therein.

1. A method of removing a photoresist structure from a substrate, comprising: supplying water vapor into an enclosed first space to be partially condensed into liquid water on surfaces of the first space, vaporizing the liquid water in the first space, supplying water vapor without any liquid water from the first space to a second space, supplying ozone gas into the second space, and uniformly applying a mixture of the water vapor and ozone gas from the second space onto the substrate on which the photoresist structure is formed, wherein the substrate is not disposed in the first space.
 2. The method of claim 1, wherein vaporizing the liquid water in the first space includes vaporizing the liquid water by transferring heat thereto.
 3. The method of claim 2, wherein the heat is transferred to the liquid water so that surfaces within the enclosed first space reach a temperature in a range of about 98° C. to 105° C.
 4. The method of claim 1, further comprising heating the substrate.
 5. The method of claim 4, wherein heating includes heating the substrate to a temperature in a range of about 98° C. to 100° C.
 6. The method of claim 1, wherein supplying water vapor into the first space includes using an inactive gas as a carrier gas.
 7. A method of removing a photoresist structure from a substrate, comprising: partially condensing a water vapor into liquid water within a first space, vaporizing the liquid water in the first space, supplying water vapor without liquid water from the first space to a second space containing ozone gas, and uniformly applying a mixture of the water vapor and ozone gas onto the substrate for removing the photoresist structure, wherein any spot phenomenon occurs within the first space and not on the substrate, and wherein the substrate is not disposed in the first space.
 8. The method of claim 7, wherein a uniform temperature distribution of the mixture is maintained as the mixture contacts the substrate. 